1. Field of the Invention
The present invention relates to a temperature detector utilizing a pyroelectric effect. More specifically, the present invention relates to a temperature detector which detects and outputs the change of temperature of an object, such as a secondary cell while it is being charged with the temperature changing as time passes, as electric signals.
2. Description of the Prior Art
A temperature detector employing a pyroelectric device for detecting the temperature rise of a battery cell at the completion of charging is used to detect the completion of charging of a secondary cell such as a Ni-Cd battery. In such a conventional temperature detector, shown in FIG. 8, a pyroelectric device 1 serving as a detecting element, and an impedance converting circuit 2 serving as a detecting circuit, are separately formed and they are electrically connected by a lead 3.
In the said conventional temperature detector, the pyroelectric device 1 serving as the detecting element is a bare thin plate, and therefore it is weak and easily damaged by a physical shock. There is a possibility of disconnection or short circuit of the lead connecting the detecting element and the detecting circuit. Measures for preventing damage due to moisture must be separately provided for the detecting element and the detecting circuit, thereby rendering the manufacturing process complicated. In addition, since the detecting element and the detecting circuit are independent from each other, the temperature detector as a whole can not be made compact.